I was sailing out on the Chesapeake about 3 years ago leaving out of port when I saw a wave of about 4 feet that was stationary. It continued to roll and even occasionally cap but was not moving. It stretched for about 6 miles from the Bridge tunnel almost to the beach in Ocean view.
We sailed over it (no Choice) with the boat peaking at almost 45 degrees and slamming down the other side. The rest of the bay on both sides was relatively calm with only 5 -8 knot winds. Not even rollers.
Best we could determine was it happened because of the tide change. It was just abit strange watching a 4 foot wave that was not moving. We sailed on watching it until out of site.